1. Technical Field
Exemplary embodiments of the present invention relate to an image forming apparatus such as a printer, a facsimile machine, or a copier.
2. Background Art
Conventionally, an image forming apparatus is known in which a latent image carrier is irradiated with light beams corresponding to image data to thus form a latent image on a surface thereof, and the thus-formed latent image is developed to obtain a visible toner image.
In such types of image forming apparatuses, for ease of replacement caused by failure or limited lifetime and for maintenance, parts or components may be provided in the form of detachably attachable units, which may include a process cartridge including a photoconductor and an optical writing device including optical elements. It is critical that units such as an optical writing device are precisely positioned within the body of the apparatus to obtain a high quality image.
An approach has been attempted to accurately position the optical writing device relative to the image forming apparatus by pressing the optical writing device against a positioning part of the apparatus body using a lever. For example, FIG. 14 illustrates an optical writing device 270 as seen from the side; and FIG. 15 is a schematic structure of a lever unit 220 to position an optical writing device 270.
As illustrated in FIG. 14, cylindrical fixed parts 231, 232 as retainer members are disposed near both lateral ends in Y-direction in the figure. The cylindrical fixed part 231 disposed at one end in the Y-direction contacts a V-shaped receiving part 242 as a positioning member disposed on the apparatus body. Further, the cylindrical fixed part 232 disposed at the other end in the Y-direction contacts a Z-direction receiving part 252 as a positioning member disposed on the apparatus body and is positioned in the Z-direction.
As illustrated in FIG. 15, the lever unit 220 includes a lever 221 mounted rotatable about a center of the cylindrical fixed part 232 as a support point of the rotation and a compression spring 222 contacting an opposite end of the rotary support point of the lever 221 and biasing the lever 221. The lever 221 includes a projection 221a that contacts a slanted portion 251 of the apparatus body.
The compression spring 222 serving as a biasing member biases an end of the lever 221 toward the Z-direction, so that the projection 221a of the lever 221 abuts the slanted portion 251 disposed on the apparatus body. As a result, the optical writing device 270 receives a reaction force from the slanted portion 251 and is pressed toward the Y- and Z-directions. Then, the cylindrical fixed part 231 disposed at one end in the Y-direction as illustrated in FIG. 14 is pressed against the V-shaped receiving part 242, and the cylindrical fixed part 232 at the other end in the Y-direction is pressed against the Z-direction receiving part 252. With this structure, the optical writing device 270 is positioned and secured to the apparatus body. In addition, when the lever 221 rotates against the biasing force of the compression spring 222, the biasing force is released, so that the optical writing device 270 can be taken out of the apparatus body.